Kelsey Juliana, a 19-year-old plaintiff, said in a statement it would be “the trial of the century” and determine young people’s right to a liveable future.

“The future of our generation is at stake,” added 16-year-old plaintiff Victoria Barrett. “I absolutely refuse to let our government’s harmful action, corporate greed, and the pure denial of climate science get in the way of that.”

Also supporting the lawsuit, on behalf of future generations, is climate scientist James Hansen.

“Science clearly establishes that our planet’s increasing energy imbalance – caused in substantial part by our government’s support for the exploitation and combustion of fossil fuel – imposes increasingly severe risks on our common future,” he said. “We will now proceed to prove our claims.”

It is the second attempt by Our Children’s Trust to sue the federal government; the first reached a dead end at the Washington DC court of appeal. To get US-wide action, lawyers need to take the case all the way from Eugene, Oregon to the Supreme Court.

Judge Coffin’s order is “revolutionary”, according to Sophie Marjanac, climate litigation expert at London-based Client Earth. “He has overturned or gone contrary to a lot of precedents in other climate cases.”

One recurrent obstacle has been a reluctance for judges to interfere on political matters. Judge Coffin took a different view.

The “intractability” of debates in Congress and state legislatures shows a need for courts to “evaluate the constitutional parameters of the action or inaction taken by the government”, he wrote.

He noted that a Netherlands court last year ordered faster greenhouse gas emissions cuts. There, the judges sided with campaign group Urgenda, saying: “The state should not hide behind the argument that the solution to the global climate problem does not depend solely on Dutch efforts.”

While that is a separate jurisdiction, Judge Coffin endorsed the principle that US regulation has “sufficient impact to redress the alleged harms”, regardless of what other countries were doing.

There was also a veiled reference to ongoing investigations into Exxon Mobil. The oil major stands accused of lying to the public about climate risk, after evidence emerged its internal research confirmed the scientific consensus as early as 1982.

“Discovery may produce evidence regarding when defendants and intervenors were aware of the harmful effects of C02 emissions and whether the public was purposely misled about those effects,” a footnote stated. Such evidence could “shock the conscience” – a standard test in US law.

Our Children’s Trust is also backing a raft of lawsuits at state level and internationally. A week ago, it supported 7-year-old Rabab Ali in filing a suit against the Pakistani government.

“Youth are rising up globally and taking their governments to court to seek protection of their inalienable rights to a stable climate system,” said Julia Olson, executive director of Our Children’s Trust.